The Stethoscope as a Germ Source

Due to constant patient contact and often insufficient disinfection, the stethoscope carries a high risk of infection throughout the medical facility. The appropriate measures, however, can enormously reduce the risk of nosocomial infections. Learn more about this below.

Constant Skin Contact as Risk Factor

The stethoscope is one of the most used instruments during a medical workday. Not only is it used in general medicine, but also in paediatrics, internal medicine, cardiology and emergency medicine as well as in many other disciplines. In order to reliably auscultate, the stethoscope must be placed directly on the skin. This guarantees that the heart, lung or intestinal noises are easy to hear. The direct skin contact, however, causes the chestpiece to come in constant contact with germs that are present on the skin. Just like on the doctor's hands, germs migrate to the stethoscope chestpiece and can be very easily transmitted.

Consequently, the hands and the stethoscope must be disinfected after contact with each patient. However, the reality is much different. While the conscientiousness for hand hygiene has greatly increased in recent years, due to various campaigns, and hand disinfection after each patient is now habitual, most still do not realise how high the risk of nosocomial infections from the use of contaminated stethoscopes is. This is because only very few and very small studies have been done.

Stethoscope Disinfection with Wipes Mostly Ineffective

Medical disinfection is typically done with a special disinfectant. Depending on if you are disinfecting surfaces, instruments or clothing, there is a chemically-specific disinfectant for each material and purpose, which guarantees a high level of germ reduction.

Stethoscopes are considered medical diagnostic instruments, but are not allowed to be disinfected by submersion. Therefore, pre-soaked disinfecting wipes are often used for stethoscope disfection.

In addition to alcohol swabs (soaked with 70% isopropyl alcohol), hydrogen-peroxide-based disinfecting wipes are also used throughout the day. It is recommended to disinfect the stethoscope chestpiece (especially the diaphragm) for 60 seconds with a hydrogen-peroxided-soaked disinfecting wipe. During these 60 seconds, the surfaces that come in contact with the patient should be firmly scrubbed.

However, a study from the University of Pennsylvania came to the conclusion that even this standardised procedure leads to sufficient germ reduction in only 50% of cases.

Certain Disinfection with UV Rays

As an alternative to uncertain disinfection with disinfecting wipes, stethoscope disinfection with UV rays offers another option. The UVC ray has a wave length from 280 to 100 nm and is especially rich in energy. UV light from this specific wave length range is damaging or even fatal to microorganisms like bacteria, viruses or fungi. The efficacy is due to the fact that cell nucleic acid absorbs the rays, leading to dimerisation and, with that, photochemical impairment.